Electric switch



R. PENN ELECTRIC SWITCH Dec, 23,

Filed April 17. 1924 fave/1227" Patented Dec. 23, 1924.

1,520,258 PATENT OFFICE.

RALPH PENN, OF DES MOINES, IOWA, ASSIGNOR OF ONE-HALF TO ALBERT PENN,

OF DES MOINES, IQWA.

ELECTRIC SWITCH.

Application filed April 17, 1924. Serial No. 707,088.

T all whom it may concern:

Be it known that I, RALPH PENN, a citizen oi the United States, and aresident of Des Moines, in the county of Polk and State of Iowa, haveinvented a certain new and useful Electric Switch, of which the followinis a specification.

y invention relates that class of electric switches designed to beoperated by 10 fluid pressure or the like.

The purpose of my invention is to provide a switch structure of thegeneral class mentioned in which the switch is actuated by a slowlyoperating power and in which 16 such mechanism is provided as willinsure approximately instantaneous movement of the movable contact awayfrom closed position.

Switches of this kind have. been made in which a roller is carried pastan angle faced apexed' member (V-shaped) or the apexed member is carriedpast the roller, and the apexed member is held against the roller or itsequivalent by means of a spring.

In such a device, where the actuating member is operated by fluidpressure or the like, a difficulty has been experienced in that there isa ssibility of the moving power operating t e actuating member to moveit to such position that the roller may be exactly at the apex of the Vor angle-faced member and the movable contact point. then permitted tohover adjacent to the fixed contact point.

5 1 When this occurs, there is danger of arcing and of burning out theparts.

It is therefore the particular purpose of my invention to provide astructure whereby quick movement of the roller past the point of theapexed member or of the apexed member past the roller will be insuredfor thus enabling the angle faces to travel quickly along the rollerwithout stopping at the apex when the switch is actuated during itsopening movement.

With these and other objects in view, my invention consists in theconstruction, arrangement and combination of the various parts of mydevice, whereby the ob ects contemplated are attained, as hereinaftermore fully set forth, pointed out 'in my claims, and illustrated in theaccompanying drawings, in which: 7

igure 1 shows an elevation of a sw1tch embodying my invention.

Figure 2 shows a transverse, detail, vertical sectional view taken onthe line 2-2 of Figure 1; and

Figure 3 shows an enlarged,-sectional, detail view of part of the switchmechanism.

In the accompanying drawings, I have shown my switch mechanism mountedupon a support or casing indicated by the reference character 10.Suitably supported on the casing or support 10 is an insulation block 11on which are the fixed contact points or members 12.

It will, of course, be understood that the fixed contacts are connectedby suitable current conducting wires 13 and'14 with a source ofelectrical energy and an electric motor or other device to becontrolled.

The switch may be used in connection with a motor for operating acompressor for filling air tanks, such for instance as are used ingarages.

Pivoted as at 15 on the support 10 is a movable member 16, which carriesat one end an arm or bracket 17. The bracket or arm 17 supports theplural leaf spring contact member 18, which is designed to coact withthe contact members 12.

A guide rod 19 is slidably mounted in the block of insulation 11 and isprovided with a shoulder 20,-which limits the movement of the bracket orarm 17 toward the block of insulation 11 in such manner as to avoidimposing too much pressure on the spring contact element 18.

Pivoted on the support 10 as at 21 is an element 22, which might becalled an actu ating arm or bar. The element 22 projects from the casingorsupport 10 and may be connected in any suitable way at its outer endwith a float,'a pressure operated diaphragm or other actuating means.

The support 10 is provided with a shoulder 23, which limits the movementof the element 22 in one direction and with a flange 24 which limitssuch movement in the other direction.

My invention has to do largely with the means for connecting theelements 16 and 22 and for imparting movement from the element 22 to theelement 16 for thereby operating the contact member 18 for openin andclosing the switch.

owever the element 22 is actuated, it is desirable that the relativelyslow movement of the element 22 should serve to actuate the movableswitch member 18 with a very quick movement, when moving from closed toopen position. 7

It is especially desirable that the begin ning of that movement shouldbe rapid.

For accomplishing these purposes, I have provided the followingmechanism for connecting the elements 16 and 22.

In the form of the invention here illustrated. the element 16 isprovided at its end opposite the bracket 17 and on the opposite side ofthe pivot with a U-shaped portion or yoke or some equivalent structure.Pivoted between the arms of the yoke 25 as at 26 is a link or a pair oflinks 27. The links 27 are pivoted to one end of an arm 28 by means of apin 29.

The arms of the yoke 25 ot' the element 16 are provided with holes orthe like 30 through which the ends of the pin 29 extend, as shown forinstance in Figure 1.

In the arrangement of the parts shown in the drawings, the arm 28 hangsdownwardly from the element 16 and is provided at its lower end with anangle-faced apexed member or portion 31 adjacent to the element 22. Theelement 22 carries an engaging member, such for instance as the roller'32 for coacting with the apexed member 31.

A coil spring 33 is fixed at one end as at 34 and is connected at itsother end with the arm 28.

In the particular form of my invention here shown, the point ofattachment of the spring 33 to the arm 28 is closer to the point of theapexed member 31 than it is to the pivot pin 29. The point of thisattachment to the arm 28 should be such that the power exerted to causethe apexed member to travel along the roller is greater than the upwardpull on the link 27 at the pin 29 before the beginning of the openingmovement of the switch.

I have shown in the drawings a particular form in which my spring can beembodied for successful operation.

It will be seen from statements made hereafter that the details ofstructure may be considerably varied under different circum stances.

In the particular form of the invention here shown, the pin 29 isarranged between the pivot point 26 and the spring 33, and

the spring 33 serves to draw the apexed member 31 into engagement withthe roller 32 and to cause the angle faces of the apexed member 31 totravel on the roller 32.

The shoulder 20 on the guide 19 limits swin ing movement of the element16 in one irection and the pivot post 34 of the spring 33 serves tolimit such swinging movement in the other direction.

Assuming that th switch is closed and the parts are in their pmitionsshown in Figure 1, the roller 32 is above the point of the apexed member31 and the s ring 33 serves to pull the arm 28 against tie roller 32 sothat the tendency of said arm is to move downwardly from its positionshown in Figure 1, with the upper angle face of the apexed membertraveling along the roller 32.

There is also, of course, a spring tension pull by the arm 28 at itsupper end on the links 27. The spring tends to swing the pivot point 29toward a line drawn through the pivot 26 parallel with the direction ofpull of the spring. The osition assumed by the links 27 is somew erebetween the line of pull on the links as above mentioned and the line ofpull downwardly.

In any event, such draft on the links 27 imposes a downward pull' on theright-hand end of the clement16 for thus holding the contact points inclosed position, and then closing the circuit through the motor, notshown.

lVhen the element 22 is actuated by pressure from a float, or any othermeans for swinging its left-hand end downwardly, it will be seen thatthe roller rides down the upper angle face of the apexcd member 31 untilit reaches the point of the apexcd member. Here then is the danger pointin the operation of switches of this kind.

It the roller should stand on such point. and the. movable contactmember should hover adjacent to the first contact members, an arc islikely to occur and the parts may be burned out.

It will be noted, however, that the pull ot the spring on the arm 28 hasa tendency to swing the lower ends of the links 27 upwardly. Thistendency is overcome prior to the time the roller 32 reaches the pointof the apexcd member, by the fact that the pu l of the spring fordrawing the upper angle face of the apexed member against the roller 32is more than enough to overcome the tendency of the arm 28 to moveupwardly.

When the roller 32 passes along the angle face of the apexed member 31,it will be obvious that the downward pull on the arm 28 will remainconstant until the apex reaches the point of tangency between the angleface and the roller. It is also evident that from the moment the apexpasses this said point of tangency, it will begin follow-- ing the arcof the-roller. and the downward pullon the arm 28 begins to decrease andwould diminish to zero when the apex reached a point on the rollerdirectly in line through the center of the roller, parallel with thepull of the spring 33.

However, after the apex of the arm 28 passes the point of tangency andthe downward pull on the arm 28 begins to decrease, there comes apointwhere the upward pull exerted by the links 27 overcomes saiddownward pull, moving the arm 28 upwardly with a very rapid movement andthereby carrying the point of the apexed member across the zero point onthe roller almost instantaneously. This is one of the vital features ofthe invention. Any hesitation or stopping ot the parts in the zeroposition is prevented, because as soon as the. point of the apexedmember crosses the-roller, the spring 33 will cause the lower angle faceof said apexed member to travel upwardly on the roller 32. whereupon thepin 29 will strike the upper wall of the holes 30, and the fur therupward movement of the arm 28 will swing the right-hand end of theelement 16 upwardly for opening the switch.

lVhen the element 22 is moved from its lower position for operating theswitch toward closing movement, it is not so important to secure theaccelerated movement of the point past the roller, because it isimmaterial if the movable switclrmember hovers at the commencement ofits closing movement.

It will thus be seen that I have provided a switch structure, whichinsures the quick relative movement of the roller and point at thecommencement of the opening movement of the switch.

Considerable variation might be made in the construction and particulararrangement of the parts.

I have found it desirable to incline the links 27 from the pivot 26toward the spring 533 as shown, largely because with this arrangementthe tendency of the spring 38 to move the links 27 is greater when thelinks 27 are at their downward limit of swinging movement, than afterthey have swung totheir upward limit of swinging movement. This is truebecause the nearer the links reach the line through the pivot26'parallel with the spring pull on the arm 28, the less power does thespring 33 exert upon them to bring them into that line.

It thus follows that with the arrangement shown, the maximum tendency ofthe spring to swing the links from their position shown in Figure 1upwardly is at the time when the switch is to be opened and the roller32 reaches approximately the point of the apex-ed member, ashereinbefore more fully explained, and this is as it should be for thenis the time when the quick movement over the point with relation to theroller should occur.

It is not necessary that the device should he made in such inanner thatthe pin 29 v strikes the element 16 during the downward movement of thelinks 27, but it is desirable that the pin 29 should strike the element16 during the upward movement of the links 27. in order that quick andpositive control may be had of the movement of the element 16 in itsswitch opening function.

I claim as my invention:

'1. In an electric switch structure of the class described, a support,two elements pivotallv mounted thereon, an arm, said arm and one of saidelements having respectively an angle faced apexed member and anengaging member for coacting with each other, a link pivoted to said armand the other of said elements for connecting them at spaced points onsaid link, and a spring for yieldingly holding said apexed member andengaging member in contact and for causing the arm to tend to swing-saidlink for moving the arm in a direction for carrying the point of saidapexed member across said engaging member.

2. In an electric switch structure of the class described, a support,two elements pivotally mounted thereon, an arm, said arm and one of saidelements having respectively an angle-faced apexed member and a coactringengaging member, a spring fixed to said support and to said arm forholding the apexed member and engaging member in contact, a link pivotedto said arm and to the other of said elements and inclined from itspivot point on said other element relative to said spring, whereby thepull of the spring on said arm tends to swing saidlink for carrying thepoint of said apexed member across said engaging member, and means forlimiting the pivotal movement of said elements.

Des Moines, Iowa, February 25, 1924.

RALPH PENN.

